From nobody Wed Feb 11 22:55:45 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AC878172D; Wed, 19 Jun 2024 10:01:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718791266; cv=none; b=KXZUJBBO8hfTaDa1vbTCFvhSq1ysFEoZa6g2IxgFwpRbIHDabodKg0/QU52YynLGOdw1kNpxdmO+fyKpYbtx94H4K7YupwyjiFU5B+NBpil8cE6HtNlWgUFSZi1kwgsxKW3lKEsYRPNvGc4n7aMZahQPmOUGqcu7jyrEtzLszlY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718791266; c=relaxed/simple; bh=56gWdS0r3P034qfTC6dEx+ZsazGXwm3BzZXrHXMJoBo=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=pXpMTGifVlmlezBht2wxDDgKrCKt7pYyO6/XtWnLS8oV3qJnl0D8GBFwggOGGiQTT0Gvq2Nrhbs2W6IZ2Ja+xVaBnK9AJDrrRBNZEnp7PJpX1sjuiiHupwOC55l8bZ00K41SPw7wtPMjwoWYx7xG1e1JuyPMfd8gtfWhm0gq2SI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=RFpGFGXD; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=BYGFFKPZ; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="RFpGFGXD"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="BYGFFKPZ" Date: Wed, 19 Jun 2024 09:55:24 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1718790924; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=39Ej7f2gzTXs2rXC0Yka/eWP1xrNbSB7cIs9Yf9GBIk=; b=RFpGFGXDrgxrFyGvqlsaVfaJwMVlv00oo1E9gHsj+WEcApIOZy+rINvIGkooNBDW2EvlDS S2FNEx9aT2qLc03CFbaDWOE57X9tory8M6ekORRjz3Qu2gfaO0b33zvTiXgp3MGaYuMYdo nuTZx5UOztS+H4dV5GmeD5ImSAWI52W7SC3G6sn2dJWbgE+WvwNEb12f6MptaZRbeabLse odYsxdw1BPxMA42s6ZyXALylaZP3oG9q1vOq1C9p5E2hikPY6eX5lqB3ra4pJsYeQ6qh2D TWfsaBD4IJF06lAJeIoeKns9ookRIvHrXnURZbcjzSxcfRyJEKAahKcb9aZb2A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1718790924; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=39Ej7f2gzTXs2rXC0Yka/eWP1xrNbSB7cIs9Yf9GBIk=; b=BYGFFKPZFTmPF5UoRGB5zEsLLY+L4j3Wk6HnBuBh4Cq2CFp4ov09GI3rGgjs7RBbCIKfWE tnCNDFTtMFaOPCAw== From: "tip-bot2 for Dave Martin" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/resctrl: Don't try to free nonexistent RMIDs Cc: Dave Martin , "Borislav Petkov (AMD)" , Reinette Chatre , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20240618140152.83154-1-Dave.Martin@arm.com> References: <20240618140152.83154-1-Dave.Martin@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <171879092443.10875.1695191697085701044.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 739c9765793e5794578a64aab293c58607f1826a Gitweb: https://git.kernel.org/tip/739c9765793e5794578a64aab293c5860= 7f1826a Author: Dave Martin AuthorDate: Tue, 18 Jun 2024 15:01:52 +01:00 Committer: Borislav Petkov (AMD) CommitterDate: Wed, 19 Jun 2024 11:39:09 +02:00 x86/resctrl: Don't try to free nonexistent RMIDs Commit 6791e0ea3071 ("x86/resctrl: Access per-rmid structures by index") adds logic to map individual monitoring groups into a global index space us= ed for tracking allocated RMIDs. Attempts to free the default RMID are ignored in free_rmid(), and this works fine on x86. With arm64 MPAM, there is a latent bug here however: on platforms with no monitors exposed through resctrl, each control group still gets a different monitoring group ID as seen by the hardware, since the CLOSID always forms = part of the monitoring group ID. This means that when removing a control group, the code may try to free this group's default monitoring group RMID for real. If there are no monitors however, the RMID tracking table rmid_ptrs[] would be a waste of memory and= is never allocated, leading to a splat when free_rmid() tries to dereference t= he table. One option would be to treat RMID 0 as special for every CLOSID, but this w= ould be ugly since bookkeeping still needs to be done for these monitoring group= IDs when there are monitors present in the hardware. Instead, add a gating check of resctrl_arch_mon_capable() in free_rmid(), a= nd just do nothing if the hardware doesn't have monitors. This fix mirrors the gating checks already present in mkdir_rdt_prepare_rmid_alloc() and elsewhere. No functional change on x86. [ bp: Massage commit message. ] Fixes: 6791e0ea3071 ("x86/resctrl: Access per-rmid structures by index") Signed-off-by: Dave Martin Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Reinette Chatre Link: https://lore.kernel.org/r/20240618140152.83154-1-Dave.Martin@arm.com --- arch/x86/kernel/cpu/resctrl/monitor.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/re= sctrl/monitor.c index 2345e68..366f496 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -519,7 +519,8 @@ void free_rmid(u32 closid, u32 rmid) * allows architectures that ignore the closid parameter to avoid an * unnecessary check. */ - if (idx =3D=3D resctrl_arch_rmid_idx_encode(RESCTRL_RESERVED_CLOSID, + if (!resctrl_arch_mon_capable() || + idx =3D=3D resctrl_arch_rmid_idx_encode(RESCTRL_RESERVED_CLOSID, RESCTRL_RESERVED_RMID)) return;